Yeah, the crashed Garlean airship caught my eye too, which is what made the gil drop for me as to what it's really meant to be a (meta) reference of. It's less a reference to FFV's Ship Graveyard (which is already in the game anyway), and more to the Island of Yamatai from 2013's Tomb Raider remake (which SE owns the IP for now).

Think about it: mystical island in the middle of the ocean that seems to draw anything passing through the area to it, whether it's a ship on sea or in the air (hence the Garlean airship), the scattered remnants of 'survivors' now inhabit the island and forming a weird cannibalistic cult there (although in Sirensong's case, they're more undead than simply crazed), and a mystical beacon being the force that draws the ships there in the first place that changes the weather surrounding the island into impenetrable tempests. And of course, a siren/wraith-like figure as the ultimate cause of the whole affair (as in, the final boss). It was too obvious to me to be mere coincidence.

Either way, I wish Sirensong hadn't been simply used as a filler dungeon to draw out the scenario as once Lorelei is defeated we're back on the ship and continue our journey without even a second thought as to what the hell was going on there. So I too am curious as to the lore of that place.